Field of the Invention
The invention relates to a method and an apparatus for the superheating of steam, which may be used, for example, in the field of energy generation, in order to convert saturated steam generated in a power station into hot steam.
Light water nuclear reactors, which include boiling water and pressurized water reactors, are used, inter alia, as power stations for energy generation. As a result of the development of heat in a reactor core, wet steam is generated in a reactor pressure vessel in the case of boiling water reactors and in steam generators in the case of pressurized water reactors. In order to reduce the moisture content of the wet steam which is initially present, steam driers are disposed in the reactor pressure vessel or in the steam generator. The saturated steam that is generated in the reactor pressure vessel has a pressure of approximately 70 bar and a temperature of approximately 286 .degree. C. and is supplied to a turbine which drives a generator for generating electric energy. As a rule an intermediate superheater is disposed downstream of the high pressure turbine since appreciable quantities of steam condense in the turbine during depressurization. The condensate which has occurred is separated in the superheater and the remaining steam is heated slightly. That process step can be avoided if superheated steam is available from the outset.
German Published, Non-Prosecuted Patent Application DE 38 36 461 A1 discloses a low temperature steam generator having a vertical cylindrical casing which is subdivided into an upper chamber and a lower chamber through the use of a horizontal partition. A hot liquid, which contains steam if appropriate, flows into the upper chamber to form a rotational flow. The liquid flows through an orifice in the partition into the lower chamber and at the same time is accelerated. As a result of the acceleration, the pressure in the liquid decreases, and steam is generated, which is discharged vertically upward from the upper chamber. The liquid leaves the chamber out of the lower chamber. However, the generated steam is not present as hot steam.
German Patent 151 464 discloses an apparatus for converting saturated steam into superheated steam. In that apparatus, steam is set in a rotational flow with the aid of a screw disposed in a casing. In that instance, condensate is generated, which flows off downward on the screw threads as the result of gravity. The screw has a hollow cylinder inside it, into which the steam can enter through slits. The steam flows vertically upward in the hollow cylinder and leaves the apparatus as superheated steam through a slide.